Electrically driven tools are well known. Thus, tools such as drills, sabre saws, orbital sanders and the like typically include in a single housing both a motor and a mechanical apparatus driven thereby. In an electric drill the driven apparatus may include a gearing arrangement for rotatably driving a gear chuck engaging a drill bit. The housing for such an arrangement typically provides a handle and a motor control. Such electrically operated drills may include a first switch, for operating the motor in one or another direction, and a second switch, such as a trigger, for turning the motor on and off, as well as varying the operating speed of the motor.
A tool designed to operate as a sabre saw typically includes a differently shaped housing to accommodate the different orientation of the tool when being used and the different requirements for handling and manipulating the tool. A control arrrangement typically provided for a sabre saw is an on/off switch. Additionally, there may be provided a speed control for the motor. Alternatively, there may be provided an on/off switch with a plurality of positions for controlling the operating speed of the sabre saw. However, in view of the unidirectional cutting operation of a sabre saw, reversal of the operating direction of the saw is to be avoided. Accordingly, sabre saws are not provided with reversing switches for the motor.
Another tool arrangement, including a specialized housing design therefor, is found in an orbital sander. Such a tool includes gearing arrangement for converting rotary motion of the output shaft of the motor to orbital motion of a sanding pad. Such tools typically have but a single switch operable in only two positions, to turn the driving motor on and off. Neither speed variation nor direction reversal are provided and are to be avoided.
Thus, it is seen that different tools of the prior art require different switching arrangements and different control switches for proper operation. Prior art tool structures provide internal wiring arrangements in the driving motors to provide variable or fixed speed and direction of rotation. Accordingly, prior art tool designs have been unable to provide a single arrangement wherein a single motor is operable as a fixed speed, fixed direction motor with one tool, a variable speed and variable direction motor with another tool, and as a variable speed fixed direction motor with yet a third tool. Such designs have thus resulted in wasteful expense by providing a separate motor with each tool since a single motor could not be provided which responded to different control switches and arrangements thereof required by different tools and which operated in one fashion with one tool and in another fashion with another tool. Because of such an inability to provide a single structure which is usuable with a plurality of tools, individual consumers have been required to purchase a plurality of motors for a plurality of tools, even though a home consumer is unlikely to be using more than one tool and one motor at one time.
The prior act has thus been deficient in failing to provide an arrangement wherein a single motor, when combined with different toolheads, operates with different characteristics, and is protected from erroneous user operation.